Good Reference Values - Fluke CertiFiber Pro User Manual

When a loss measurement is negative. This occurs when there

was a problem when you set the reference. For example, an
endface was dirty or the testers were cold.
Do not disconnect the test reference cords from
the modules' output ports after you set the
reference. If you do, you will change the amount
of optical power that enters the fiber and the
reference will not be correct.

Good Reference Values

Reference values must be in these ranges:
Multimode 50/125 µm fiber: -19.4 dBm to -26.5 dBm

Multimode 62.5/125 µm fiber: -17.5 dBm to -23.0 dBm

Singlemode fiber: -1.0 dBm to -6.0 dBm

If your reference value is outside of the applicable range given
above, clean and inspect all connectors then set the reference
again. Do this even if the tester lets you use the value.
If your test reference cords and connectors are in good condition,
and you use the correct procedure to set the reference, the
reference value will not change by more than approximately
0.4 dBm.
Chapter 3: How to Certify Fiber Cabling
Requirements for Reliable Fiber Test Results

Caution
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